1. Field of the Invention
This invention relates to the field of homogenizing, tissue disruption, and to a device which is particularly suited to tasks where risks of contamination must be minimized while keeping the sterilization process uncomplicated.
2. Description of Related Art
Many of today""s protocols for the preparation of highly contaminant sensitive materials, such as gene research and hazardous disease studies, call for the utilization of mechanical shear and cavitation devices such as the Willems Polytron which was disclosed in U.S. Pat. No. 2,789,800. These devices generally feature a hollow outer shaft (stator) and a central inner shaft (rotor) extending axially through the outer shaft. The stator is formed at the lower end with a plurality of circularly arranged teeth, usually spaced at regular intervals. The lower end of the rotor generally includes a pair of downwardly extending teeth, which are in close proximity to the stator""s teeth. When immersed in a mixture, and upon rotation of the rotor, the mixture is drawn in the rotor, and additional ultrasonic pressure field is set up within the mixture, thereby causing disintegration of the solid particles and resulting in homogenization of the mixture. The combination of these forces effectively circulate, disrupt, and dissolute solid particles into a homogenous liquid. This method of processing constitutes a majority of the approach used in the field of mechanical shear.
In the Willems Polytron and similar rotor-stator devices, windows were used in the tops and sides of the stators to allow pressure release in the upper stator. The need for windows can cause drainage from the top of the stator thus adding to material loss as well as possible contamination issues. However due to the high speeds at which this equipment runs and also viscosity of the media being processed, media tends to travel up inside the stator device. This is a tendency in all rotor-stator devices. If there are no windows in the stator, when the rotor spins at high speeds it is effectively sealed and a low pressure area is created in the top of the stator. The higher pressure of the fluid being processed allows the sample to rise higher in the tube and thus risk entering the motor.
Using a simple principle that was demonstrated by Archimedes, a screw pump, and adapting the theory to our device we have come up with a unique approach to solve the fluid rising problem and resulting potential for eliminating sample contamination.
According to one preferred form, the present invention is a disposable disruptor agitator tool for processing a sample. The tool preferably includes a stator and a rotor defining an axis, the rotor preferably being disposed for rotation within the stator. One of the ends of the rotor preferably has four vanes adapted to couple to a drive means for rotating the rotor. The rotor preferably also has a screw thread on an outer portion thereof, the screw thread extending along a substantial portion of the rotor and configured to provide a reverse pumping action to the sample. Another end of the rotor preferably has two opposed blades for shearing the sample. The stator is preferably generally tubular in shape, with one end of the stator having L-shaped reliefs adapted to receive a mating adapter. The stator preferably also has circular pressure relief openings therein. Another end of the stator preferably has axially elongated openings extending therefrom for cooperating with the rotor blades to permit the sample to be expelled from the stator while shearing solid particles of the sample.
In a further preferred embodiment of the invention, the stator and rotor optionally are formed of plastic. In still another embodiment of the invention, the stator optionally has an enlarged portion at one of its ends, the enlarged portion having alternating recesses and ribs.